1993 GS500, Full Yoshi, Lunchbox, 137.5 Jets, still rich?!

[SlimKlim]

I've been workng with my bike and trying to get it running well. I got myself all licensed, and took it for its first ride last night two weeks after buying it with the 147.5 jets in it. It ran well and felt right but it was running rich, like really really rich. Emitting a plume of smoke over 3500, especially under acceleration, some under deceleration, and not so much cruising.

Last night it had 147.5 mains, 3 shims on the slides, and 2.5 turns out on the air/fuel screws.

This morning I woke up and put some 137.5s in it and didn't change anything else (I figured one thing at a time), and took it for another ride. Still emits a large plume of smoke but now its more around 4500. It also feels "Crisper" like it responds to throttle better than last night. It also "pops and burbles" decelerating, I don't know if thats normal for these bikes, my car does it and its perfectly normal, but I thought I'd mention it. revving it up and getting a good whiff of the smoke, it doesn't smell like oil, it definitely smells like something running rich, not that singed nasty smell of something burning oil, however, if you wipe your finger inside the tailpipe, you pick up a pitch black slime, that has no strong smell either way.

So now specs are 137.5, 3 shims, 2.5 turns out. I'm not sure how the shims and air/fuel screws change the ratio, as far as which direction you go to add more air. So I wanted to ask for advice from the pros. I also don't know if I'm completely off base here, so I want to check in and get some advice before I keep tinkering with the wrong thing or make anything worse.

Side note: Riding the bike is AWESOME! As someone with almost no experience it feels smooth and easy to control, easy to put where I want it and riding in general is about the most fun you can have with your pants on. I've also enjoyed the time I've spent working on this bike, so much simpler than working on a car.

I also realized deer are a whole new kind of obstacle on a bike. O__O

[utgunslinger13]

Check the wiki, there are base guidelines on where your settings should be for the mods on your bike.  I'm no expert, and can't offer any settings suggestions but would definetly recommend checking that list out.

[SlimKlim]

Thanks, I checked out out and it seems like everyone is running a 147 or a 150, which doesn't seem to make much sense. They all seem to only have 1 washer and 3 turns out, maybe i could try that but really I'd just be tinkering. I don't know if it would change much, and I'm not sure why mine's so different. I mean we're talking some pretty noticeable smoke here.

[SlimKlim]

Okay, took two shims out of the slides so now the specs are:

137.5 main, 1 shim, 2.5 turns out. Its feels even better and is smoking less, but is still unleashing a good cloud if I twist it at 3k, and will smoke under heavy throttle and when coming off of it, but will be okay cruising/moderate throttle. The volume and density of the smoke seems to be improving, so now maybe the next thing to do is set the air/fuel screws with the bike running, I'll have to look up that procedure again.

EDIT: Also used the Veypor for a 0-60, dyno run today. First time I've ever done it, 5.74 seconds, and since Im still barely out of my riding virginity, I wasn't really worried about launching it or slamming the shifts, so I'd say that's pretty good. According to it I put down 35hp and 27tq (I think). I don't know how accurate that all is though.

[Eklipse]

Depends on your elevation, too.

[SlimKlim]

Is it normal for an old 500 to smoke a little bit when operating properly? Its still smoking more than it obviously should at the moment, but I doubt going out there to adjust the air/fuel is going to magically make it all go away. My roommate drives a stock mitsubishi ralliart (little turbo thing) and it emits a puff of soot if he mashes it. Its only 2 years old, and its done it since it was new, its just how it is.

Just wondering, I'm not sure what else to change, I could remove another shim, I don't know if I have any 135 jets, but regardless of elevation, it seems like a wildly leaner set up than everyone else.

[Homer]

Don't know if you saw that thread I made.
I found the book to that Veypor.  The box was in my storage room, and you saw how cluttered it was.  
I've never used that dyno function, so it sounds like you're doing okay.    Only 35 HP?  Aww...  
The old engine must have had more!  


It could very well be the rings, Klim.  If you've re-jetted your butt off, and it's not going away...
I know how bad that looks, since I'm who sold it to you.  But, like I told you - Werase said it had a fresh top-end and didn't know anything else about it.  Paid him $200 to have it put in.  Drove it home, and then parked it. 
He said he couldn't guarantee it, and I told you the same thing.  That's why I tried to line up a new one for you. 

I'd try to find Dgyver, if he's still around.  Or Sledge.  If it is the rings, they might have a set of those larger pistons for a 555 kit. 

[SlimKlim]

The rings around the piston you mean? I don't think its burning oil to be honest, I'll check the level and see if its changed.

It really smells like fuel, so I think this motor is in pretty good shape, I'm going to go out and do the air/fuel procedure and I'll report back to see if that changes anything.

If that doesn't do it I'm going to quit screwin with it and let it smoke, I'll wait for the parts to make it pass VA inspection and then I'll have my mechanic buddy help me look at the motor and see if its the valve seals or piston rings or something.

[jeremy_nash]

how are your float heights?  if they are too high, it will make it run rich. I have 142.5's  with 40 pilot.  lunchbox filter and aftermarket pipe with no baffles, and it runs great!

[jeremy_nash]

what mods are done to it? filter, pipe?  never mind, its in your title

[SlimKlim]

That has to be it, unless it actually is burning oil, that smells like gas.

I just came in from playing with it. I went down to the 135s, took out another shim and left it at 2.5 turns out, still runs okay but is spewing smoke just like before.

I did notice, one time even though I ran it until it stalled the bowls were literally full of gas, I know you can check the float height with a length of hose, but is there a DIY on how to adjust it? Hopefully that will be it and clear it up, even if I end up having to rejet and shim the thing again. The float height is the only other thing I can possibly think of, if its not that, then I can't smell anymore and its burning oil. Which means I have iskoos to deal with.  

Anyone have a link to a good float adjustment diy?

EDIT: NVM, found it in the wiki. I was going to throw in the towel, but I'm going to do this before I pack it in for the night and see if I can't start the work week feeling like I made some big progress in my little project here.

EDIT TWO: I don't understand the wiki.  Can anyone break it down for the slow kid? I flip the carb upside down with the bowl off and the float still in? Now the what should be how far from what? And what do I use to measure it?

[SlimKlim]

I sort of figured out how to adjust the float height. I ended up bending the tab from about 3mm of clearance to about 6mm of clearance with the floats down as low as they could go, this yielded what seemed to be .57in on my calipers of float height, which I attempted to measure at the point where I could no longer blow air in through the fuel line. This however, had no effect on the smoking issue. I measured the float height, and it was about 3/8 of an inch below the gasket on the right, and about 1/8 above on the left, although now that I think about it, the bike was on the side stand, so that might account for the difference.

I didn't ride it again after adjusting it, seeing all the smoke revving it up in neutral was all I needed to know. What the hell do I do with this thing? Adjusted (hopefully) float height, 135 main jets, no shims, 2.5 turns out. With a full exhaust and lunchbox, that should be an extremely lean set up, and its spewing smoke everywhere.

Maybe its not fuel, maybe its burning oil. What do I do?  

EDIT: Also the smoke is blue, NOT a good sign, it doesn't smell like a traditional car burning oil, but I'm pretty damn sure its burning oil at this point.

I haven't noticed it leaking in the garage. However, my symptoms are pretty dramatic and described as above, should I go straight to piston seals as the culprit? If I'm going to have to go in and change the seals, is there anything else I should do while I'm in there? Could it be something else?

[AccidentalF]

If it were that rich you'd see the exhaust sooted to high heaven and plugs would be black.  Blue smoke = oil, Black smoke = fuel.  Sounds like you're burning oil.  Shouldn't damage anything to run it, as long as it has oil to burn, but yeah it's not right.  Do a leakdown test to be sure where it is coming from: could be piston rings, valve seals/guides, or both.

[utgunslinger13]

I have a set of stock rings sitting in the box o parts if thats what it end up being.  Not looking to make any money off of it, any reasonable offer and its yours.

[SlimKlim]

I have a set of stock rings sitting in the box o parts if thats what it end up being.  Not looking to make any money off of it, any reasonable offer and its yours.

PM sent. If I'm going into the motor I might as well replace everything I can, cause I ain't goin in there again.

I'm also not doing it alone, I have a friend who is an incredible mechanic, and I'm hoping a 12 pack of beer and a decent hourly rate will help me get this done in reasonable time, I want to ride, not have a garage ornament. I want to get this project done and not let it sit around.

[Paulcet]

I sort of figured out how to adjust the float height. I ended up bending the tab from about 3mm of clearance to about 6mm of clearance with the floats down as low as they could go, this yielded what seemed to be .57in on my calipers of float height, which I attempted to measure at the point where I could no longer blow air in through the fuel line. This however, had no effect on the smoking issue. I measured the float height, and it was about 3/8 of an inch below the gasket on the right, and about 1/8 above on the left, although now that I think about it, the bike was on the side stand, so that might account for the difference.

I didn't ride it again after adjusting it, seeing all the smoke revving it up in neutral was all I needed to know. What the hell do I do with this thing? Adjusted (hopefully) float height, 135 main jets, no shims, 2.5 turns out. With a full exhaust and lunchbox, that should be an extremely lean set up, and its spewing smoke everywhere.

Maybe its not fuel, maybe its burning oil. What do I do?  

EDIT: Also the smoke is blue, NOT a good sign, it doesn't smell like a traditional car burning oil, but I'm pretty damn sure its burning oil at this point.

I haven't noticed it leaking in the garage. However, my symptoms are pretty dramatic and described as above, should I go straight to piston seals as the culprit? If I'm going to have to go in and change the seals, is there anything else I should do while I'm in there? Could it be something else?

Use the tube method to adjust float levels, on center stand.  You don't even need to remove the carbs to adjust the tang.  You drain the bowls (turn off fuel first), remove the bowl, tweak the tang up or down as required, replace the bowl and refill and recheck.  Repeat as necessary.  So, do you say it runs rich because of the smoke?  How do the plugs look?

[SlimKlim]

Yes, thats what was leading me to think that, but after adjusting them in 100% sure its oil. Its blue in color and playing all day with the carbs had minimal effect on it.

I'm gonna need some piston rings, and valve seals and guides, anything else to replace while im in there?

[Paulcet]

As someone already did something with the head, I think it would be a good idea to do a compression test/leakdown test first.  Valve guides are likely to be fine.  Maybe ride 1000 miles and see how much oil actually burns.

[SlimKlim]

A lot. Like a whole lot, probably 1/2 qt in the 80 mi or so I rode it this weekend. It was pretty much off the dipstick when I checked it, and I had to bring it back up to the full mark, dunno how much it really was. This isn't like an oh shoot my bike is eating up oil, ill get that fixed one day, this needs to be done before I can really start to ride it. I don't think there is an easy way to express just HOW much oil comes out of this thing. Thats why at first I thought it was just epically rich, but I'm still learning I guess.

I guess the rings are just shot, I dunno about anything else.

[SlimKlim]

I'm going to do a compression and leak down test tonight, and pull the headers off and look into the exhaust to see if its all wet in there. Here are my thoughts. Homer gave me an extra head from his old motor when I bought the bike, which could turn out to be a god send. If the compression test comes back okay, and its the valve seals and guides that are shot, I can have someone visually inspect that extra head and possibly just swap it out, and roll on.

Likewise, if it the compression test comes back poor, and it looks like I'm going to have to replace the rings, do work on one of the two heads, and buy a whole new gasket set. It may be above my pain tolerance.

One thought is to buy another motor for it, figure $400 to get one here, and try to sell this engine for parts and all the other engine parts I have for it, to help offset the cost, considering how expensive a gasket set is and everything.

If it turns out to be the worst case scenario, I may have to sell the bike, and try again with something else.  Best case scenario, compression and leakdown tests show the bottom end is in tip top shape, and the head Homer gave me (which looks beautiful to me, but I'm no expert) is in good condition, and all I end up doing is popping the head off and swapping the other on without spending much money.

From what I hear this motor had recent head work, however, if the valve guides were going, someone could have replaced the seals for a temp fix, and then the play in the guide caused the valve to eat up the new seal, causing this problem.

More to come when I get home from work tonight, any suggestions are welcome.